Help to locate problem on amp

[Chris F]

I have a LSS which I have had for 3 weeks now (it was demo used when I bought it). I am very happy with the amp. However, today when I played on channel 2 on the amp, and switched to 5w mode, the amp became silent. Switching bacl to 15 and 30w, it gave off sound again. Then I tested channel 1, and exactly the same thing happened in the 5w mode...dead silence. But not in 15 and 30w.

I play only at home, and do play at low volumes (have a little kid). I looked in the back, and all tubes seemed to glow. Could it still be a tube problem (that it perhaps just happened) or something else? The 4w has worked before on other days.

Anyone has experienced this? I have to drive for a 1 1/2 to take it back to the dealer.

I would really appreciate help on this.

Thanks,
Chris

 

[sec34gtr]

If it were a tube problem, it would be either a rectifier tube, or one of the 2 outer power tubes. I can't recall which, but either the left-most or right-most power tube is the only one functioning in 5W mode.

This should be an easy fix, hopefully.

However, I currently have one of these in my shop exhibiting the same behavior and I can't seem to fix it... But it's worked on others!!!

Good luck!!

 

[Chris F]

Thank you for your advice. I hope it is easily fixable. Love the amp, and feel its a keeper, so I hope it won't be a continuing anormal behavior.

 

[Platypus]

Definitely the rectifier tube, 5Y3... this is a well known problem with the LSS.

Sad to see the same problems over and over on Mesa amps.. makes you wonder sometimes :roll:

 

[Chris F]

Thanks for the tip. I phoned the dealer and he will look at it on Wednesday. He more or less echoed your tips and said to that he had seen that on several Mesas.

Great to have so many people here on this forum helping out

Chris

 

[Chris F]

Problem with LSS sorted. I followed the advice from you guys here on the forum and bought new tubes and changed them. It was the powertube. No it is working perfectly again.

Thanks

Chris